Electroplating barrel constructed from two disparate plastics

ABSTRACT

A polyhedral rotatable electroplating barrel in which the axial ribs or struts and end heads are made of a thermoplastic resin whose deflection temperature as well as tensile and flexural strengths exceeds those of the thermoplastic resin used for the perforate panels with means interconnecting the ribs, heads and panels so that the panels are free to expand without buckling in all three dimensions into grooves in the ribs and heads.

United States Patent Noonan [451 Feb. 13, 1973 [54] ELECTROPLATING BARREL 3,442,783 5/1969 Kirkpatrick et a]. ..204/213 CONSTRUCTED FROM TWO DISPARATE PLASTICS Z' ;f :2? ssls an xammeron [75] Inventor: Walter F. Noonan, Wallingford, Pa. Attorney Mcclure & Millman [73] Assignee: Westlake Plastics C0., Lenni, Pa.

[57] ABSTRACT [22] Flled: June 1971 A polyhedral rotatable electroplating barrel in which [21] Appl. No.: 150,985 the axial ribs or struts and end heads are made of a thermoplastic resin whose deflection temperature as well as tensile and flexural strengths exceeds those of [52] US. Cl. ..204/213, 118/418, 8245/5896 the thermoplastic resin used for the perforate panels 4 [51] I t Cl C23) 5/78 with means interconnecting the ribs, heads and panels 90 so that the pan ls are free to expand without buckling 1 o earc 1 118" in all three dimensions into grooves in the ribs and l heads.

[56] References Cited 12 Claims, 12 Drawing Figures UNITED STATES PATENTS 3,084,916 4/1963 Scharmer et al. ..259/89 SI ISIQIXI PATENTED FEB I 31973 SHEET 10F 2 avg fox". WALTER F. NOONAN PATENTEDFEBI 3 I913 SHEET 2 OF 2 WALTER F. NOONAN %CZWY' A TIOAWL'KQ ELECTROPLATING BARREL CONSTRUCTED FROM TWO DISPARATE PLASTICS This invention relates generally to electroplating barrels or cylinders in which many small articles are plated at one time and in particular to rotary polyhedral (referred to in the industry as polygonal) barrels with perforated panels through which the electroplating solution is pumped due to rotation thereof.

Heretofore, polygonal barrels have been fabricated of such materials as hard rubber, polypropylene and methyl methacrylate polymers to resist the corrosive effects of the plating solutions, hard rubber at relatively high operating temperatures in the order of magnitude of 225F., methyl methacrylate at temperatures not exceeding 180F. and polypropylene at operating temperatures in the range of l75-2l2F., as indicated in the Nielson U.S. Pat. No. 3,256,170.

The most widely used material at present is polypropylene because it possesses relatively good load-support and operating temperature characteristics and is economical to fabricate into the barrel parts. The sides of the barrel are perforate panels secured between axially extending ribs which are in turn secured to end heads or flanges. One of the sides is removably clamped in place to serve as a door. All of these parts are made of polypropylene whose deflection temperature at a load of 264 psi is in the order of magnitude of l 35l40F.

A most common practice is to weld the perforate panels to the ribs. It is also common to operate the barrels at temperatures above that recommended, that is at l80-200F., which causes the distortion of the ribs and plates in particular with the result that the door cannot be removed. The distortion can also rupture the welds.

It is the primary object of this invention to provide an economical plastic polygonal barrel in which the aforesaid disadvantages of panel distortion and possible weld rupture are eliminated while improving the strength of the barrel.

A further object of the invention is to provide a polygonal barrel of the character described in which the perforate panels are made of a thermoplastic resin whose thermal characteristics permit the panels to be subjected to operating'temperatures of l80-200F. whereas the axially extending ribs and end heads are made of a thermoplastic resin whose thermal characteristics permit the ribs and heads to be subjected to operating temperatures in the order of magnitude of about 260F., and loosely interconnecting these members in such a manner that when the barrel is operated at l80200F as is the common practice at present, the ribs and heads will not expand, but the expansion of the panels will be taken up in the interconnection between them. and the ribs and heads to thereby prevent distortion of the panels.

Another object of the invention is to provide a polygonal barrel of the character described in which the thermoplastic resin from which the ribs and heads are made is of the same class as that used for the panels except that it is glass filled thereby at the same time imparting flexural strength to the ribs and heads while raising its deflection temperature.

Another object of the invention is to provide a polygonal barrel as above described in which the fiber glass strands are embedded in the resin used to make the ribs and heads in such a manner that they are below the surface .of said members to minimize their attach by fluorides.

In a preferred embodiment of the invention the axially extending ribs and end heads are made of a glass filled polypropylene and the perforate panels are made of virgin polypropylene, the ribs each including axially extending angulated grooves receiving the side edges of the panels, the heads being provided at their inner faces with recesses to receive the ends of the ribs and connected by grooves to receive the ends of the panels, the heads being ultimately secured to the ribs, the grooves exceeding the thickness of the panels, the ends of the panels being spaced from the inner walls of the head grooves and the side edges of the panels being spaced from the inner walls of the rib grooves to allow the panels to expand lengthwise, laterally and vertically, when the barrel is operated in the range of l-200F. relative to the undistorted ribs and heads to prevent buckling of the panels. This construction also permits ready removal and replacement of the various members should they become defective for any reason.

These and other objects of the invention will become more apparent as the following description proceeds in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevational view of one form of the electroplating barrel made in accordance with the invention;

FIG. 2 is an end elevational view thereof looking from the line 2--2 of FIG. I; 7

FIG. 3 is a sectional view taken on the line 3-3 of FIG. 1;

FIG. 4 is an enlarged view of the area 4 of FIG. 3;

FIG. 5 is an end view of the inner face of an end head or flange;

FIG. 6 is an axial sectional view taken on the line 6- 6 of FIG. 1;

FIG. 7 is a sectional view taken on the line 77 of FIG. 4;

FIG. 8 is an enlarged sectional view of a portion of a rib or head illustrating the manner in which the fiber glass strands are embedded in the resin beneath the surface thereof;

FIG. 9 is an end view of the outer face of another form of one of the heads;

FIG. 10 is a sectional view taken on the line l0 10 of FIG. 9;

FIG. 11 is an end view of the outer face of yet another type of head; and

FIG. 12 is a sectional view taken on the line 12-12 of FIG. 11.

Specific reference is now made to the drawings in which similar reference characters are used for corresponding elements throughout.

The polyhedral barrel, usually hexahedral, but which can have more or less than six sides, is shown generally at 10 and is intended to be suspended by suitable hangers from an overhead rail and rotated horizontally while partially immersed in an electroplating solution. See Electroplating Engineering Handbook, Second Edition, by Graham et al.-, Chapter 25, entitled Barrels. Conventionally such a barrel consists essentially of panels 12 having perforations 14 therethrough, nonperforate axially extending ribs 16 to which the panels are connected and generally circular end plates, heads or flanges l8 and 20 securing the ribs. The end plates or heads are provided with the usual bearing bosses 22. to suspend the barrel by hangers (not shown) from an overhead rail (not shown), the bosses having bores to provide access for electrodes (not shown) into the barrel.

To rotate the barrel, a gear is associated with one of the heads 20 which is engaged by another gear driven by a suitable overhead motor. In the form of the invention shown in FIGS. 1-8, a separate toothed gear wheel 24 is bolted as at 26 to the head 20 with spacers 28 intervening between the head 20 and gear wheel 24. In the form of invention shown in FIGS. 9 and 10, it is the head 30 itself which is provided with peripheral gear teeth 32. In the form of invention shown in FIGS. 11 and 12, no gears are used. Rather, the head 34 is in the form of a pulley having a peripheral groove 36 for engagement by a belt to be driven thereby as seen in the Gill U.S. Pat. No. 3,394,071.

The perforate panels form the faces of the polyhedron except that for one face the panel 38 serves as a door for access to the interior of the barrel. As seen in FIG. 3, the door is generally thicker than the panels, is removably supported on the adjacent ribs 40 and 42 and there retained by suitable clamping devices 44 well known in the art. See, for example, the Neilson U.S. Pat. No. 3,256,170.

The perforate panels 12 are made of a thermoplastic resin such as virgin polypropylene (unmodified homopolymer resin) whose deflection temperature at 264 psi is in the order of magnitude of l35l40F. It has been found that under the loads encountered in electroplating and because of fatigue and other factors, polypropylene panels distort in the range of operating temperatures of l80-200F., especially towards the upper range.

The ribs 16 and heads 18 and 20 are made of a thermoplastic resin having good tensile and flexural strength and a deflection temperature under load so that the ribs and heads will not distort until a temperature of about 260F. is attained. It has been found that polypropylene filled with -20 percent by weight of fiber glass strands is economical to mold into the ribs and heads, has excellent tensile and flexural strength and deflection temperatures at 264 psi of about 280-305F. Such a glass filled resin is shown in FIG. 8. The glass filled resin is molded in such a manner that the fibers 46 extend beneath the outer surfaces 48 and 50 thereof to leave areas 52 and 54 which are free of the glass fibers or strands, thus minimizing attack on the faces of the ribs and heads which may be exposed to fluorides.

Other thermoplastic resins having flexural and tensile strengths above that of virgin polypropylene and higher deflection (and hence operating) temperatures which can be used for the ribs and heads are asbestosfilled polypropylene, sold by Hercules Powder as profax 66FIA which has a deflection temperature at 264 psi of about 190F. and mineral-(talc) filled polypropylene sold by Hercules Powder as profax 66F3which has a deflection temperature at 264 psi of about 177F. The aforementioned glass-filled polypropylene is superior.

As will be seen in FIG. 3, the ribs 40 and 42 to support the removable door 38 are molded to contain angulated axially extending grooves 56 in their opposed sides which permits the door to slip into the grooves and rest on the inner walls 58 of the grooves.

The panels 12 are so supported on the ribs and heads and the latter so connected that when the barrel is operated near or somewhat beyond 200F., the panels will be able to expand longitudinally (axially), laterally (circumferentially) and vertically while the ribs and heads do not, thereby preventing the panels from buckling.

Each rib 16 extends axially between the heads 18 and 20 and constitute the apices or corners of the polyhedron. While ribs may have any desired profile, a substantially rectangular cross-section is desired with bevels 60 at the interior surface thereof to minimize sharp edges which may injure the items to be plated as they tumble in the electroplating solution during rotation of the barrel. Opening through the opposite axially extending sides 62 and 64 of each rib are substantially U-shaped grooves 66 and 68 which extend at angles to each other equivalent to the interior angle required for completion of the polyhedron when the perforate panels are inserted therein as shown in the drawings.

The grooves 66 and 68 are of depth to provide inner end or web surfaces 70 and 72, the distance between the inner surface 70 of the groove of one rib and the inner surface 72 of the groove of the next rib, when the barrel is fully assembled, exceeds the width of the panel 12 which is received in said grooves so that spaces 74 and 76 are provided between the side edges 78 and 80 of the panel and said inner surfaces 70 and 72 of the grooves. Thus, the panels are free to expand laterally when the barrel is operated in the range of l 80-200F.

As seen in FIG. 5, the inner surface 82 of each head 18 and 20 is provided with recesses 84 approximating the cross-sectional dimensions and configurations of the ribs 16 and recesses 86 and 88 approximating the cross-sectional dimensions and configurations of the door ribs 40 and 42. Interconnecting the recesses 84 are grooves 90 which exceed the cross-sectional dimensions of but are of the same configuration as the panels 12. A further wider groove 92 which approximates the cross-sectional dimensions and configurations of the door interconnects the recesses 86 and 88. When the ends of the ribs are received in their respective recesses 84, 86 and 88 and the ends 92 of the panels in their respective grooves 90, the heads 18 and 20 are then secured as by bolts 94 to the ribs. The depth of each panel groove 90 is such, as seen in FIG. 7, that the distance between the inner surface 96 thereof in one head 18 and the inner surface of the panel groove 90 in the other head 20, when the barrel is assembled, exceeds the length of the panel 12 to provide a space 98 between said inner groove surface 96 and the end 92 of the panel.

The same arrangement of recesses 84, 86 and 88 for the ribs and grooves 90 for the panels are used in the heads 30 and 34 of the forms of the invention illustrated in FIGS. 9-12. The interconnected rib recesses and panel grooves are shown diagrammatically as 100 in FIGS. 9 and 10 and 102 in FIGS. 11 and 12.

Thus if the barrel should be operated at a temperature at or somewhat above l80longitudinally F., the perforate panels can expand longitidinally into the spaces 98of the head grooves 90 and laterally into the spaces 74 and 76 of the rib grooves while the ribs and heads remain unexpanded since they will not distort at said range of l80-200F., in view of their higher deflection temperatures.

It should also be noted that the.thickness of the panels 12 is less than that of the rib grooves 66 and 68 and the head grooves 90 to allow expansion of the polypropylene in this dimension (i.e., vertically) as well. However, the difference in said thicknesses need not be of the order of magnitude of the spaces 74 and 76 in the rib grooves beyond the side edges of the panel or of the order of magnitude of the spaces 98 in the rib grooves 90 beyond the ends 92 of the panels.

While preferred embodiments have here been shown and described, a skilled artisan may make variations without departing from the spirit of the invention and the scope of the appended claims. For example, the door 38 may be made of talc-filled or asbestos filled polypropylene to secure the advantages of increased tensile and flexural strength and a higher deflection temperature without presenting the difficulties in drilling or providing perforations therein which would be encountered if the door were made of the glass-filled polypropylene.

What is claimed is:

1. A polyhedral electroplating barrel comprising axially extending perforate panels forming the sides thereof, axially extending ribs forming the corners thereof, and heads secured to said ribs, means loosely supporting the side edges of said panels in said ribs including grooves in said ribs receiving the side edges of said panels so that for each panel a space is provided between one face of the panel and the corresponding wall of the groove and between one side edge of the panel and the corresponding wall of the groove, and means loosely supporting the end edges of said panels in said heads, including grooves on the inner surface of said heads receiving the end edges of panels so that for each panel a space is provided between one end edge of the panel and the corresponding wall of the head groove and between one face of the panel and the corresponding wall of the head groove, said ribs and heads being made ofa thermoplastic resin whose deflection temperature, flexural and tensile strengths exceed those of the resin from which the perforate panels are made so that when the barrel is operated in the temperature range of about l80 200F., the panels will expand relative to the ribs and heads and not buckle.

2. The barrel of claim 1 wherein said perforate panels are made of polypropylene and said ribs and heads are made of glass-filled polypropylene.

3. The barrel of claim 1 wherein said perforate panels are made of polypropylene and said ribs and heads are made of asbestos-filled polypropylene.

4. The barrel of claim 1 wherein said perforate panels are made of polypropylene 'and said ribs and heads are made of talc-filled polypropylene.

5. The barrel of claim .2 wherein said glass -filled polypropylene contains fiber. glass strands embedded in the resin with no glass strands exposed at the surface of said ribs and heads to thereby prevent attack by fluorides.

6. The barrel of claim 5 wherein said glass-filled polypropylene contains lO-2O percent by weight of lass. g 7. The barrel of claim 1 wherein said means loosely supporting the side edges of said panels in said ribs includes substantially U-shaped grooves coextensive with and opening through the sides thereof at an angle to each other substantially that of the included angle of the polyhedron, each groove exceeding the thickness of a panel and being of such depth that the distance between the inner end or web surface of one groove receiving a panel and the inner end or web surface of the groove of the next rib receiving the same panel exceeds the width of the panel.

8. The barrel of claim 7 wherein said means loosely supporting the end edges of said panels in said heads includes grooves in the inner surfaces of said heads of the same shape as said panels but exceeding their thickness, the distance between the inner end surface or web of the groove of one head receiving a panel and the inner end surface or web of the groove of the other head receiving the same panel exceeding the length of said panel.

9. The barrel of claim 8 wherein said glass-filled polypropylene contains fiber glass strands embedded in the resin with no glass strands exposed at the surface of said ribs and heads to thereby prevent attack by fluorides.

10. The barrel of claim 9 wherein said glass-filled polypropylene contains l0-20 percent by weight of glass.

11. The barrel of claim 9 wherein said inner surfaces of said heads also include recesses corresponding in shape to said ribs, said panel grooves in said inner surfaces communicating with and interconnecting said recesses so that said ribs and panels are received in said recesses and grooves respectively.

12. A polyhedral electroplating barrel comprising axially extending ribs of polypropylene filled with 10-20 percent by weight of fiber glass whose fibers are not exposed at the'surface thereof, grooves opening at the included angle of the polyhedron through the sides of each rib, perforate panels of polypropylene substantially coextensive with said ribs loosely received in said grooves so that for each panel a space is provided between one face of the panel and the corresponding wall of the groove and between one side edge of the panel and the corresponding wall of the groove, end heads made of the same glass-filled polypropylene as said ribs, grooves in the inner surfaces of said heads loosely receiving the end edges of said panels so that for each panel a space is provided between one end edge of the panel and the corresponding wall of the head groove and between one face of the panel and the corresponding wall of the head groove, and means securing said heads to said ribs so that when the barrel is operated at temperatures in the range of about l200F., the ribs and heads will not expand and the panels will be free to expand in all directions and hence not buckle. v 

1. A polyhedral electroplating barrel comprising axially extending perforate panels forming the sides thereof, axially extending ribs forming the corners thereof, and heads secured to said ribs, means loosely supporting the side edges of said panels in said ribs including grooves in said ribs receiving the side edges of said panels so that for each panel a space is provided between one faCe of the panel and the corresponding wall of the groove and between one side edge of the panel and the corresponding wall of the groove, and means loosely supporting the end edges of said panels in said heads, including grooves on the inner surface of said heads receiving the end edges of panels so that for each panel a space is provided between one end edge of the panel and the corresponding wall of the head groove and between one face of the panel and the corresponding wall of the head groove, said ribs and heads being made of a thermoplastic resin whose deflection temperature, flexural and tensile strengths exceed those of the resin from which the perforate panels are made so that when the barrel is operated in the temperature range of about 180*- 200*F., the panels will expand relative to the ribs and heads and not buckle.
 2. The barrel of claim 1 wherein said perforate panels are made of polypropylene and said ribs and heads are made of glass-filled polypropylene.
 3. The barrel of claim 1 wherein said perforate panels are made of polypropylene and said ribs and heads are made of asbestos-filled polypropylene.
 4. The barrel of claim 1 wherein said perforate panels are made of polypropylene and said ribs and heads are made of talc-filled polypropylene.
 5. The barrel of claim 2 wherein said glass-filled polypropylene contains fiber glass strands embedded in the resin with no glass strands exposed at the surface of said ribs and heads to thereby prevent attack by fluorides.
 6. The barrel of claim 5 wherein said glass-filled polypropylene contains 10- 20 percent by weight of glass.
 7. The barrel of claim 1 wherein said means loosely supporting the side edges of said panels in said ribs includes substantially U-shaped grooves coextensive with and opening through the sides thereof at an angle to each other substantially that of the included angle of the polyhedron, each groove exceeding the thickness of a panel and being of such depth that the distance between the inner end or web surface of one groove receiving a panel and the inner end or web surface of the groove of the next rib receiving the same panel exceeds the width of the panel.
 8. The barrel of claim 7 wherein said means loosely supporting the end edges of said panels in said heads includes grooves in the inner surfaces of said heads of the same shape as said panels but exceeding their thickness, the distance between the inner end surface or web of the groove of one head receiving a panel and the inner end surface or web of the groove of the other head receiving the same panel exceeding the length of said panel.
 9. The barrel of claim 8 wherein said glass-filled polypropylene contains fiber glass strands embedded in the resin with no glass strands exposed at the surface of said ribs and heads to thereby prevent attack by fluorides.
 10. The barrel of claim 9 wherein said glass-filled polypropylene contains 10- 20 percent by weight of glass.
 11. The barrel of claim 9 wherein said inner surfaces of said heads also include recesses corresponding in shape to said ribs, said panel grooves in said inner surfaces communicating with and interconnecting said recesses so that said ribs and panels are received in said recesses and grooves respectively. 